Device for treating disc-like articles

ABSTRACT

A device for treating a disc-like article with a fluid, includes elements for dispensing a fluid onto the article and a chuck for holding and rotating the article around an axis perpendicular thereto. The chuck includes a base body, a drive ring, and gripping members for contacting the article at its edge. The gripping members are eccentrically movable with respect to the center of the article. The eccentric movement of the gripping members is driven by a drive ring rotatably mounted to the base body, so that the drive ring is rotatable against the base body around the axis. The relative rotational movement of the drive ring against the base body is carried out by either holding the base body and rotating the drive ring or by holding the drive ring and rotating the base body, whereby the to-be-held-part (drive ring or base body) is held without touching the respective to-be-held-part by magnetic force.

TECHNICAL FIELD

The invention refers to a device for supporting and rotating a disc-likearticle with a rotor comprising a support for supporting the disc-likearticle, wherein the rotor is located within a process chamber.

BACKGROUND ART

WO 2007/101764 A1 discloses a device for fluid treatment of a disc-likearticle comprising a rotary head for holding and rotating a disc-likearticle around a rotation axis, a drive means to suspend and drive therotary head without contact, the drive means being arranged radiallyaround the rotary head, a substantially cylindrical wall, which issubstantially concentric to the rotation axis, wherein the cylindricalwall is arranged between the rotary head and the drive means.

A suitable driving mechanism is described in U.S. Pat. No. 6,485,531.With the herein disclosed active magnetic bearing and drive mechanismthe distance of stator to rotor is limited.

Some solutions of holding the disc-like article are provided in U.S.Pat. No. 5,845,662. These holding means are however complicated to openor require a minimum spin speed in order to securely hold the disc-likearticle. Another problem is that at very high spin speeds they may holdthe disc-like article with a force that could be high enough to harm thedisc-like article.

It is an object of the invention to provide a device which securelyholds a disc-like article during treatment.

DISCLOSURE OF INVENTION

The invention solves the problems by providing a device for treating adisc-like article comprising a chuck for holding and rotating thedisc-like article about an axis A perpendicular to the disc-likearticle, wherein the chuck comprises a base body, a drive ring, which isrotational symmetrical arranged to the base body, and gripping membersfor contacting the disc-like article at its edge, wherein the grippingmembers can be moved eccentrically with respect to the axis A bytwisting the drive ring relative to the base body about the axis A,wherein the drive ring is held by magnetic forces.

Such a configuration is especially helpful if the chuck is held androtated by magnetic bearings (e.g. active magnetic bearings as describedin U.S. Pat. No. 6,485,531 or WO2007/101764A1). However, such amechanism can also be used in combination with an ordinary chuck drivenby a spindle.

In one embodiment the device comprises dispensing means for dispensing afluid onto the disc-like article and a chuck for holding and rotating adisc-like article about an axis A perpendicular to the disc-likearticle, the chuck comprising a base body, a drive ring, and grippingmembers for contacting the disc-like article at its edge, wherein thegripping members are eccentrically movable with respect to the centre ofthe disc-like article, wherein the eccentric movement of the grippingmembers is driven by a drive ring, wherein the drive ring is rotatablemounted to the base body, so that the drive ring is rotatable againstthe base body around the axis A and thereby driving the grippingmembers, wherein the relative rotational movement of the drive ringagainst the base body is carried out by either holding the base body androtating the drive ring or by holding the drive ring and rotating thebase body, whereby the to-be-held-part (drive ring or base body) is heldwithout touching the respective to be held part by magnetic force. Inthis case the to-be-rotated-part (base body or driving ringrespectively) can be rotated without touching the respectiveto-be-rotated-part by magnetic force.

Such magnetic force typically is established between two elements of amagnetic couple. Such couples can e.g. be one of the following:

-   -   2 permanent magnets—the first magnet fixed to the drive ring;        the second magnet mounted to a moving member, which can be        radially moved (radially with respect to the axis A). Such a        moving member can be driven e.g. by a pneumatic cylinder or an        electric linear motor.    -   one permanent magnet and one electromagnet—the first magnet        fixed to the drive ring; the electromagnet mounted to a        non-rotating part of the device (e.g. the chamber wall)

In another embodiment the base body is formed as a hollow ring with anannular chamber accommodating the drive ring. Such hollow ring maycomprise two or more parts. Such parts can be welded, screwed or gluedtogether.

Preferably the chuck is magnetically levitated. This can be carried outby an active magnetic bearing (as described in U.S. Pat. No. 6,485,531)or by a bearing supported by high temperature superconducting magnets.Such a driving mechanism comprising high temperature superconductingmagnets is further described by published patent applications derivingfrom Austrian patent application no. A 1987/2008. With such aconfiguration it is possible that all parts of the spin mechanism aswell as all parts of the gripping mechanism can be sealed againsttreatment fluids. The parts for activating the opening/closing mechanismcan be located outside a closed process chamber.

In one embodiment the drive ring is a gear ring and the gripping membersare cams eccentrically projecting for smaller gears (eccentric withrespect to the rotation axis of the smaller gears), which are driven bythe gear ring. When the gear ring is twisted against the base body thesmaller gears rotate and therewith the cams (pins), which projecteccentrically from the smaller gears, alter their distance to the axisA. Thereby the cams grip the disc-like article at its edge or releasethe disc-like article. It shall be understood that the projecting camscan either be mounted to the smaller gears or that the cams and thesmaller gears can be formed out of the same piece of material.

Preferably the drive ring is held in standby position by an elasticmember (e.g. a spring), whereby the gripping members are urged intoclosed position. When the drive ring is held by magnetic forces and thebase body is twisted the drive ring is spanned against the chuckingpower. Then the disc-like article is placed between the grippingmembers. Thereafter the drive ring and base body are twisted back againand the gripping members contact the disc-like article's edge.Consequently the force of the elastic member securely chucks thedisc-like article.

In a preferred embodiment the device further comprises a wallsurrounding the chuck and during treating the disc-like article thechuck is freely levitated within the wall. In this case the elements,between which the magnetic force shall be established, have to beconfigured so that the drive ring can be securely locked while the basebody of the chuck is turned about a certain angle (e.g. 1°-10°).

In a preferred embodiment the wall surrounding the chuck is part of aclosed chamber. This has the advantage that the chuck and therewith thedisc-like article rotate within the chamber whereas the mechanisms fordriving the chuck and for opening the gripping members remain outsidethe chamber. The chamber needs to be opened only for entering andexiting the disc-like article.

In another embodiment dispensing means are provided for unobstructeddispensing of fluids onto both sides of the disc-like article. This ishelpful if the dispensed fluids comprise liquids.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1 a-1 f show a schematic top view of a device according to oneembodiment of the invention in operation.

FIGS. 2 a-2 f show different views of a device according to oneembodiment of the invention.

FIGS. 3 a-3 c show another embodiment of the invention.

MODE(S) FOR CARRYING OUT THE INVENTION

With reference to FIG. 2 a-2 f a device 200 according to one embodimentof the invention shall be described.

FIG. 2 a shows a cross-sectional perspective view of a device 200according to one embodiment of the invention.

FIG. 2 b shows an enlarged view of the detail D2 b (of FIG. 2 a).

FIG. 2 c shows a side view of the detail D2 b.

FIG. 2 d shows an enlarged view of the detail D2 d (of FIG. 2 a).

FIG. 2 e shows the same view as FIG. 2 b however the permanent magnet255 for locking the tooth gear ring are brought into close proximity tothe permanent magnets 233 of the chuck.

FIG. 2 f shows an enlarged detail of a cross-sectional perspective viewthrough the pin shaft 227 and the pin 228.

The device 200 comprises a chamber, an annular chuck 220 for grippingand rotating a wafer (disc-like article) and a stator 280.

The chamber comprises a cylindrical wall 260, a bottom plate 265 and atop plate (not shown). An upper dispensing tube 263 is lead through thetop plate and a lower dispensing tube 267 through the bottom plate 265.

The stator 280 is mounted to a stator base plate 205 concentric to thecylindrical wall 260. The stator base plate 205 can be moved in axialdirection with respect to the cylinder axis of the cylindrical wall 260,e.g. with pneumatic lifting means. The stator base plate 205 and thestator 280 mounted thereto have central openings, which have biggerdiameter than the outer diameter of the cylindrical wall 260. The topplate can also be moved in axial direction in order to open the chamber.In closed position the top plate is sealed against the cylindrical wall.

The stator 280 comprises several coils for axial and radial bearing andfor driving the rotor 285, which is part of the annular chuck. Sucharrangement is called active bearing and is further described in U.S.Pat. No. 6,485,531.

The diameter of the annular chuck 220 is smaller than the inner diameterof the cylindrical wall so that it can freely levitate and rotate withinthe cylindrical wall 260. The annular chuck 220 comprises an inner chuckbase body 221 with an annular groove circumferentially surrounding theoutside of the inner chuck base body 221, the annular groove serves asthe bearing for the drive ring 230.

The drive ring 230 is embodied as a gear ring 230 with inwardly facingteeth 231. The inwardly facing teeth 231 drive the teeth of a pin shaft227 (see FIG. 2 f).

This embodiment has six downwardly oriented pin shafts 227, each ofwhich has a small gear, which is driven by the drive ring 230. The pinshafts 227 are mounted so that they can turn about an axis A, which isparallel to the rotation axis of the annular chuck.

Eccentric with respect to the pin shaft's rotation axis A a pin 228 ismounted to the pin shaft 227 so that the pin alters its distance to thecentre of the annular chuck when the pin shaft is turned by the drivering 230. In other words the pin is radially moved when the drive ring230 is twisted against the chuck base body 221. In order to mount thedrive ring 230 into the annular groove of the chuck base body 221 thedrive ring 230 consists of two separate segments, which are fixedtogether when inserted into the annular groove. The chuck base 221 andthe drive ring 230 are connected via a helical spring (not shown) sothat the drive ring 230 urges the pins 228 into positions, which arecloser to the centre of the annular chuck 220.

Two permanent magnets 233 are mounted to the tooth gear ring 230. Aplurality of at least twenty-four rotor magnets 285, which are permanentmagnets, are evenly arranged around the chuck base body 221. These rotormagnets 285 are part of the drive and bearing unit namely part of therotor (elements of the active bearing), which is mounted to the chuckbase body 221.

The plurality of rotor magnets 285 and the drive ring 230 carrying thepermanent magnets 233 are encapsulated in a hollow annular spaceprovided by the chuck base body 221, outer lower chuck cover 222, andthe rotor magnet cover 229. Such rotor magnet cover 229 can be astainless steal jacket. The covers 222 and 229 are annular andconcentric with the chuck base body 221.

When assembling the chuck 220 the pin shafts 227 are inserted from aboveinto their respective seats so that the pin shafts tightly seal againstthe chuck base body 221 as shown in FIG. 2 f. Each pin shaft 227 isfixed in their position with a screw 224. Additionally each pin shaftmay be pressed into its seat by a helical spring between the pin shaftand the screw.

Attached to the stator base plate 205 is the stator and active bearingunit 280 which is concentrically arranged with respect to thecylindrical wall 260. The bearing unit 280 corresponds with the rotormagnets 285 therefore levitating, bearing and rotating the chuck 220.

Below the active bearing unit 280 there are two pneumatic cylinders 250mounted to the stator base plate 205. On the distal ends of the rods ofthe pneumatic cylinders 250 locking magnets 255 (permanent magnets) arearranged. The locking magnets correspond to the permanent magnets 233 ofthe drive ring 230. The pneumatic cylinders 250 are arranged so that thelocking magnets 255 can be radially moved with respect to the axis ofthe cylindrical wall 260.

When the pins shall be opened e.g. to release a wafer the followingprocedure is conducted. The stator base plate 205 is lifted andtherewith the levitating chuck 220 so that the cylindrical wall 260 isno longer in the gap between the locking magnets 255 and the chuck 220(see FIG. 2 e). Thereafter the pneumatic cylinders 250 move the lockingmagnets 255 in close proximity to the chuck 220 and the chuck is turnedso that the permanent magnets 233 and therewith the drive ring 230 islocked by the locking magnets. Now the chuck is turned while the drivering stands still and thus the pins 228 open. Alternatively the chuckbase body might stand still while the pneumatic cylinders are moved sothat the locking magnets tangentially turn (along the circumference ofthe chuck), whereby the drive ring is turned.

With reference to FIGS. 1 a-1 f if the operation of the pin openingmechanism shall be described. The FIGS. 1 a-1 fare schematic views of across-section along about a plane I-I as shown in FIG. 2 c.

FIG. 1 a shows the device in a standby position. Herein a 120°-segmentof the device is shown. The chuck 120 with a chuck base body 121 and anouter wall 122 accommodate the tooth gear ring 130. The gear ring 130has inwardly viewing teeth 131. The pin shafts 127 with the pins 128 arearranged so that their gears bite on the teeth 131 of gear ring 130(drive ring). The pin shafts sit in their respective seats of the chuckbase body 121.

The chuck base 121 and the drive ring 130 are connected via a helicalspring 140 so that the drive ring 130 urges the pins 128 in a position,which is closest to the centre of the annular chuck 120. The force ofthe helical spring 140 is visualized by the two small arrows S in FIG. 1b. Around the circumference there are three such helical springs 140arranged, which are mounted to the chuck base body 120 at mounting point125 and to the gear ring at mounting point 135.

Locking magnets 155 are fixed to the distal end of the pneumaticcylinder 150. The Locking magnets 155 correspond to the permanentmagnets 133 of the gear ring 130.

For opening and closing the pins e.g. to grab and release a wafer thefollowing procedure is conducted. The levitating chuck 120 is lifted sothat the cylindrical wall 160 (shown in FIG. 1 e) is no longer in thegap between the locking magnets 155 and the chuck 120. Therefore thecylindrical wall is not shown in FIGS. 1 a-1d and FIG. 1 f. Thereafterthe chuck 120 is turned so that the permanent magnets face the lockingmagnets 155 (FIG. 1 a).

Then the pneumatic cylinders 150 move (see arrow L) the locking magnets155 in close proximity to the chuck 120 (see FIG. 1 b), however withouttouching the chuck 120, so that the permanent magnets 133 and therewiththe drive ring 130 is locked by the locking magnets.

Now the chuck 120 is turned counter-clockwise (Tccw) while the drivering 130 stands still and thus the pin shaft turns clockwise (To) andthe pins 128 open (FIG. 1 c), while the helical springs 140 areexpanded. A wafer W (dotted line) is placed between the pins.

Then the chuck base body 121 is turned clockwise (see FIG. 1 d) and thepin shafts turn counter-clockwise (Tc) so that the pins move towards thecentre and the pins securely hold the wafer W. The helical springs 140ensure this closed position.

Thereafter the locking magnets are withdrawn, and the stator (not shown)is lowered with the chuck 120 so that the cylindrical chamber wall 160surrounds the chuck (see FIG. 1 e). Thereafter the chamber cover islowered and thus the chamber is sealed. The process is started, meaningthat the chuck rotates and different liquids in a sequence are dispensedfrom above and below.

After the process the chamber is opened again and the stator is liftedagain. For releasing the wafer the locking magnets 155 are brought inclose proximity to the chuck. The chuck is turned counter clockwise(Tccw) so that the pins open (To; see FIG. 1 f).

FIGS. 3 a and 3 b show another embodiment of the invention. FIG. 3 bshows a cross-sectional view along the plane II-II (see FIG. 3 a). FIG.3 a shows a cross-sectional view along the plane III-III (see FIG. 3 b).In FIG. 3 a a 120°-segment of the device is shown. The chuck 320 with achuck base body 321 and an outer wall 322 accommodate the drive ring 330with inwardly viewing slanted plane 332. The pins 328 are tiltablearranged so that they can tilt about an axis X in order to move one endof the pin toward and from the centre of the wafer. The axis X isparallel to a tangent of the wafer W so perpendicular to the planeII-II. The pin bearing may have a spherical shape and sits in itsrespective spherical seat of the chuck base body 321. Such seats servealso as sealing. For each pin a helical pressure spring 326 (pin closingsprings) is provided to urge the pin in closed position. In this way thepart of the pin located within the annular space of the chuck is kept incontact to the corresponding slanted plane 332 of the drive ring 330.

The chuck base 321 and the drive ring 330 are connected via a helicalspring 340 so that the drive ring 330 allows the distal ends of the pins328 in a position, which are closest to the centre of the annular chuck320. Around the circumference there are three such helical springs 340arranged, which are mounted to the chuck base body 320 at mounting point325 and to the gear ring at mounting point 335.

The force of all pin closing springs 326 together can be selected strongenough so that the expansions springs 340 may be omitted or even suchsprings may be arranged to urge the drive ring into the oppositedirection so that the slanted planes 332 may keep contact with the pinseven if the pins grip a wafer on their distal ends.

Locking magnets 355 are fixed to the distal end of the pneumaticcylinder 350. The Locking magnets 355 correspond to the permanentmagnets 333 of the gear ring 330.

For opening and closing the pins e.g. to grab and release a wafer thefollowing procedure is conducted. The levitating chuck 320 is lifted sothat the cylindrical wall 360 (shown in FIG. 3 c) is no longer in thegap between the locking magnets 355 and the chuck 320. Therefore thecylindrical wall is not shown in FIGS. 3 a and 3 c. Thereafter the chuck320 is turned so that the permanent magnets face the locking magnets 355(FIGS. 3 a and 3 c).

Then the pneumatic cylinders 350 move the locking magnets 355 in closeproximity to the chuck 320, however without touching the chuck 320, sothat the permanent magnets 333 and therewith the drive ring 330 islocked by the locking magnets.

Now the chuck 320 is turned counter-clockwise (Tccw) while the drivering 330 stands still and thus the pins are tilted about the axis X andthe pins 328 open (FIG. 3 c), while the helical tension springs 340 andare expanded and the helical compression springs 326 are compressed. Awafer W (dotted line) is placed between the pins. Then the chuck basebody 321 is turned clockwise (see FIG. 1 d) and the pins are tilted sothat the pins move towards the centre and the pins securely hold thewafer W. The helical pin springs 326 ensure this closed position.

The further procedure is analogous to what is described with referenceto FIGS. 1 a-1 f.

1. A device for treating a disc-like article with a fluid, the devicecomprising at least one dispenser for dispensing a fluid onto adisc-like article and a chuck for holding and rotating a disc-likearticle about an axis A perpendicular to the disc-like article, thechuck comprising a base body and gripping members for contacting thedisc-like article at its edge, wherein the gripping members are radiallymovable with respect to the axis A, and wherein the gripping membersextend downwardly from an obliquely-inclined radially-inwardly facingannular surface of the base body.
 2. The device according to claim 1,wherein the obliquely-inclined radially-inwardly facing annular surfaceof the base body surrounds the gripping members and overhangs adisc-like article when held by the gripping members.
 3. The deviceaccording to claim 1, wherein the radial movement of the grippingmembers is driven by a drive ring, wherein the drive ring is rotatablymounted to the base body, so that the drive ring is rotatable againstthe base body around the axis A and thereby driving the grippingmembers, wherein the relative rotational movement of the drive ringagainst the base body is carried out by either holding the base body androtating the drive ring or by holding the drive ring and rotating thebase body, wherein the to-be-held-part (drive ring or base body) is heldwithout touching the respective to-be-held-part by magnetic force. 4.The device according to claim 3, wherein the to-be-rotated part (basebody or driving ring respectively) is rotated by magnetic force withouttouching the respective to be rotated part.
 5. The device according toclaim 3, wherein the base body is formed as a hollow ring with anannular chamber and where the drive ring is accommodated within theannular chamber.
 6. The device according to claim 1, wherein the chuckis freely levitated by a magnetic bearing.
 7. The device according toclaim 1, wherein the chuck is levitated and rotated by an activemagnetic bearing or a bearing supported by high temperaturesuperconducting magnets.
 8. The device according to claim 3, wherein thedrive ring is a gear ring and the gripping members are cams eacheccentrically mounted to a respective smaller gear that is in meshingengagement with the gear ring.
 9. The device according to claim 3,wherein the drive ring is held in standby position by an elastic member,whereby the gripping members are urged into closed position.
 10. Thedevice according to claim 1, wherein the device further comprises a wallsurrounding the chuck and during treating the disc-like article thechuck is freely levitated within the wall.
 11. The device according toclaim 10, wherein the wall surrounding the chuck is part of a closedchamber.
 12. The device according to claim 1, wherein plural dispensersare provided for unobstructed dispensing of fluids onto both sides ofthe disc-like article.